The present invention generally relates to a thermostatic fluid controller, and more particularly, to a thermostatic fluid controller for showerhead assemblies and faucet assemblies featuring two thermostatic cylinders for precluding water between different pre-determined temperatures for an increased closing time over a broader range of temperatures.
Recent legislation requiring products to prevent accidents involving scalding water indicates an increased interest in devices that can control water, namely hot water. Scald-burn injuries can range from minor to life-threatening and can even cause death in certain cases. These injuries are frequently caused by water temperature fluctuation in the plumbing system. Occurrences such as toilets being flushed are common causes of water temperature fluctuations. As an example, when a toilet is flushed while a shower or faucet with a proper hot-to-cold water ratio is running, cold water is used to refill the tank of the toilet and, consequently, the water pressure, from the cold water pipes, decreases. The result is that less cold water is available for the hot/cold mix flowing to the shower, bathtub, or faucet, thereby causing the water mix to increase in temperature. In many instances, the temperature for hot water can be too hot in buildings that share a common boiler or water heater, i.e. apartment buildings, hospitals, or nursing homes. Frequently water temperatures in these residential and commercial water supplies can exceed 130° F., temperatures at which an adult can easily be scalded or burned. Children are especially vulnerable to being scalded from overly-hot bath or shower mix because they have thinner skin than adults. A child can sustain a third degree burn from exposure to 140° F. water for a mere three seconds.
The water temperature in buildings that share a common boiler or water heater is often kept higher than recommended so that a sufficient source of hot water is available to a great number of users at a given time. This means that a way to regulate the temperature at the “end-line” location in buildings with a large common boiler is critical.
The serious consequences of over-hot water temperatures has caused a majority of states to enact legislation requiring new construction to incorporate anti-scald devices that feature a means of controlling maximum water temperatures delivered to the faucet and showerhead assemblies. These regulations, however, only apply to new construction and do not mandate the use of anti-scald fixtures in older buildings. Since the legislation applies only to new construction, many of the anti-scald devices currently known in the field relate to devices incorporated “in-line” or behind the walls adjacent to the showers, bathtubs or sinks, or are otherwise difficult to access and require the skill of a professional plumber.
Such “in-line” devices are incorporated within the lines of the home or business plumbing systems. These devices are normally installed prior to the interior finishing and “dry-walling.” These devices often have a reset capability for normal use. However, when the device is damaged, defective, or is unable to be reset, it is very difficult to repair or replace the device without a trained plumber. Furthermore, the devices are incorporated behind the walls, so it is necessary to tear out portions of the wall to replace or repair the device. Such destruction can be very costly. Furthermore, a device that electronically controls the temperature of water often has a sensor component, which is mounted behind the wall of the shower. In situations of an electrical malfunction or short circuit, the electronic device is only accessible by a plumber. Such systems can lead to high repair costs.
An “in-line” device is incorporated for use with existing faucet assemblies or showerhead assemblies, and is described in U.S. Pat. No. 5,584,432 (“'432 patent”). The '432 patent teaches a structure for blocking the flow of water using a shape memory alloy spring. The shape memory alloy spring stiffens at a specific temperature against a valve to preclude the flow of water from exiting the valve. The shape memory alloy spring softens at a second pre-determined temperature to enable the flow of water to exit the valve.
The previously described regulating devices in the prior art are for “in-line” locations rather than “point-of-use” locations. The Safe Drinking Water Act amendments of 1996, 104 P.L. 182 (1996), distinguishes between point-of-entry and point-of-use devices in §105. Point-of-entry devices are located at a plumbing systems “in-line” location, or in other words, located within the plumbing supply pipes. Point-of-use devices are located at the systems “end-line” location, or in other words, the apparatus the consumer uses.
The present invention is an “end-line” device integrated into a unique faucet assembly or shower head assembly. The present invention offers an “end-line” anti-scald device providing relatively inexpensive scald prevention in both new and existing homes and/or commercial buildings. The invention's location in the water supply system, integrated into an “end-user” device offers inexpensive and efficient scald prevention. This “end-line” location offers a device that blocks the flow of excessively hot water and is located in a showerhead assembly or a faucet assembly. Previous devices are incorporated directly into the plumbing system behind the walls of a building. The present invention enables the user to incorporate an anti-scald system into pre-existing plumbing systems and can be easily replaced by the user. Replacement occurs by replacement of the unit at the end of the water line.
The previous devices utilize a single thermostatic cylinder having a specific “ramp-up” time period. These devices do not account for instances where the change in fluid temperature instantly increases because the slow reaction time of the single thermostatic cylinder. Therefore, there is a need for thermostatic fluid controllers that regulate fluid flow when fluid temperature changes at a moderate rate and when fluid temperature changes at a high rate. The present invention solves this problem by incorporating a primary and secondary thermostatic cylinder system designed to operate at separate temperatures as well as over different temperature ranges.